Ch 1 Flashcards
Microbiology revolves around two themes:
- understanding basic life processes
- applying that knowledge to the benefits of humans
___ are excellent models for understanding cellular processes in unicellular and multicellular organisms.
Microbes
Microbes play important roles in ___, ___, and ___.
Medicine, agriculture, and industry
The importance of microorganisms:
- oldest form of life
- largest mass of living material on earth
- carry out major processes for biogeochemical cycles
- can live in places unsuitable for other organisms
- other life forms require microbes to survive
The cell is..
A dynamic entity that forms the fundamental unit of life
Cytoplasmic (cell) membrane:
Barrier that separates the inside of the cell from the outside environment
Cytoplasm:
Aqueous mixture of macromolecules, ions, and ribosome
Ribosomes:
Protein-synthesizing structures
Cell wall:
Present in most microbes; confers structural strength
All cells have the following in common:
- cytoplasmic membrane
- cytoplasm
- ribosomes
- cell wall
Prokaryotes
- no membrane-enclosed organelles, no nucleus
- generally smaller than eukaryotic cells
Eukaryotes
- DNA enclosed in a membrane-bound nucleus
- cells are generally larger and more complex
- contain organelles
Genome:
A cells full complement of genes
Eukaryotic DNA is ___ and found within the ___.
Linear, nucleus
Eukaryotic cells usually have more than one ___.
Chromosome
Eukaryotic cells typically have ___ copies of each chromosome.
Two
During cell division, nucleus divides by ____.
Mitosis
During sexual reproduction, the genome is halved by ___.
Meiosis
Prokaryotic cells generally have a single, circular DNA molecule called a ___.
Chromosome
DNA aggregates to form the ___.
Nucleoid region
Prokaryotes also may have small amounts of extrachromosomal DNA called ___ that confer special properties.
Plasmids
E. coli genome vs. human cell
E. coli
4.64 million base pairs
4,300 genes
Human cell
1,000x more DNA per cell than E. coli
7x more genes than E. coli
Metabolism:
Chemical transformation of nutrients
Reproduction:
Generation of two cells from one
Differentiation:
Synthesis of new substances or structures that modify the cell
Communication:
Generation of, and response to, chemical signals
Movement:
Via self-propulsion, many forms in microbes
Evolution:
Genetic changes in cells that are transferred to offspring
The process of change over time that results in new varieties and species of organisms
Enzymes:
Protein catalysts of the cell that accelerate chemical reactions
Cells store and process information that is eventually passed on to offspring during reproduction through ___ and ___.
DNA and evolution
DNA stands for:
Deoxyribonucleic acid
Transcription:
DNA produces RNA
DNA produces RNA
Transcription
Translation:
RNA makes protein
RNA makes protein
Translation
Growth:
The link between cells as machines and cells as coding devices
Last universal common ancestor (LUCA):
Common ancestral cell from which all cells descended
Earth is ___ years old
4.6 billion
First cells appeared between ___ and ___ years ago
3.8-3.9 billion
The atmosphere was anoxic until about ___ years ago.
2 billion
Metabolisms were exclusively ___ until evolution of oxygen-producing phototrophs
Anaerobic
Life was exclusively microbial until about ___ years ago.
One billion
Phylogeny:
- Evolutionary relationships between organisms
Ribosomal RNA (rRNA) is excellent for determining ___.
Phylogeny
Relationships visualized on a ___ ___.
Phylogenetic tree
Relationships can be deduced by comparing ___ ___ in the different specimens
Genetic information
Comparative rRNA sequencing has defined three distinct lineages of cells called ___.
Domains
Three domains:
Bacteria (prokaryotic)
Archaea (prokaryotic)
Eukarya (eukaryotic)
Archaea are more closely related to ___ than ___.
Eukarya than bacteria
___ ___ were the ancestors of multicellular organisms.
Eukaryotic microorganisms
From the LUCA, evolution proceeded to form two domains:
Bacteria
Archaea
Archaea later diverged to form two domains:
Archaea
Eukarya
Microorganisms exist in nature in populations of interacting assemblages called ___ ___.
Microbial communities
The environment in which a microbial population lives is its ___.
Habitat
___ refers to all living organisms plus physical and chemical constituents of their environment.
Ecosystem
___ ___ is the study of microbes in their natural environment.
Microbial ecology
Diversity and abundances of microbes are controlled by ___ and ___ ___.
Resources (nutrients) and environmental conditions (temp, pH, O2)
The activities of microbial communities can affect the chemical and physical properties of their ___.
Habitats
Microbes also interact with their ___ and ___ environment.
Physical and chemical
Ecosystems are greatly influenced by ___ ___.
Microbial activities
Extremophiles:
Bacteria and archaea that can grow in extremely harsh environments
- very hot or very cold
- very acidic or very caustic
- very salty or very osmotically stressing
- very high pressure
Global estimate is ___ cells
5x10^30
Most microbial cells are found in ___ and ___ subsurfaces.
Oceanic and terrestrial
Microbial ___ is significant, and cells are key reservoirs of essential nutrients.
Biomass
Microorganisms can be both ___ and ___ to humans.
Beneficial and harmful
Many more microorganisms are ___ than are ___.
Beneficial, harmful
Many aspects of agriculture depend on ___ ___.
Microbial activities
Positive impacts of microorganisms and agriculture
- nitrogen-fixing bacteria
- cellulose-degrading microbes in the rumen
- regeneration of nutrients in soil and water
Negative impacts of microorganisms and agriculture
Diseases in plants and animals
High numbers of microorganisms occur in ___ and ___ ___.
Colon and oral cavity
Positive impacts of microorganisms and the human GI tract
- synthesize vitamins and other nutrients
- compete with pathogens for space and resources
Positive impacts of microorganisms and food
- microbial transformations yield
Negative impacts of microorganisms and food
Microorganisms can cause food spoilage
The role of microbes in production of biofuels
Methane, ethanol, hydrogen
Bioremediation:
The role of microbes in cleaning up pollutants
Biotechnology:
Genetic engineering of microbes to generate products of value to humans, such as insulin
Microorganisms and their genetic resources
Exploitation of microbes for production of antibiotics, enzymes, and various chemicals
Microbiology began with the ___.
Microscope
Who was the first to describe microbes?
Robert Hooke
What did Robert Hooke do?
Illustrated the fruiting structures of molds
Who was the first to describe bacteria?
Antoni van Leeuwenhoek
Who discovered that living organisms discriminate between optical isomers?
Louis Pasteur
Who discovered that alcoholic fermentation was a biologically mediated process?
Louis Pasteur
Who disproved theory of spontaneous generation?
Louis Pasteur
Who developed vaccines for anthrax, fowl cholera, and rabies?
Louis Pasteur
When Pasteur disproved the theory of spontaneous generation it led to..
The development of methods for controlling the growth of microorganisms
Pasteur developed vaccines for ___, ___ ___, and ___.
Anthrax, fowl cholera, and rabies
Who demonstrated the link between microbes and infectious diseases?
Robert Koch
Koch developed techniques for..
Obtaining pure cultures of microbes
Koch identified causative agents of ___ and ___.
Anthrax and tuberculosis
Koch discovered that using solid media provided a simple way to optain ___ ___.
Pure cultures
Colonies:
Masses of cells
Koch observed that colonies have different ___, ___, and ___.
Shapes, colors, and sizes.
Microbial diversity:
Field that focuses on nonmedical aspects of microbiology
Who developed enrichment culture technique?
Martinus Beijerinck
Enrichment culture technique
Microbes can be isolated from natural samples in a highly selective fashion by manipulating nutrient and incubation conditions
Who proposed concept of chemolithotrophy?
Sergei Winogradsky
Chemolithotrophy
Oxidation of inorganic compounds linked to energy conservation
Winogradsky demonstrated that specific bacteria are linked to specific ___ ___.
Biogeochemical transformations
Major subdisciplines of applied microbiology:
- medical microbiology
- immunology
- agriculture microbiology
- industrial microbiology
- aquatic microbiology
- biotechnology
Medical microbiology:
Infectious diseases
Immunology:
Immune system
Agricultural microbiology:
Microbes associated with soil
Industrial microbiology:
Production of antibiotics, alcohols, and other chemicals
Aquatic microbiology:
Water, wastewater, and drinking water
Biotechnology:
Products of genetically engineered microorganisms
Basic science subdisciplines in microbiology
- microbial systematics
- microbial physiology
- microbial ecology
- microbial biochemistry
- bacterial genetics
- virology
Microbial systematics:
The science of grouping and classifying organisms
Microbial physiology:
Study of the nutrients that microbes require for metabolism and growth and the products that microorganisms generate
Microbial ecology:
Study of microbial diversity and activity in natural habitats
Microbial biochemistry:
Study of microbial enzymes and chemical reactions
Bacterial genetics:
Study of heredity and variation in bacteria
Virology:
Study of viruses
Binary fission
Asexual reproduction
Positive chemotaxis
Place sugar - moves towards
Negative chemotaxis
Place acid - moves away
“Hypo”
High heat
Saccharophiles
Sugar loving
Pathogenic
Able to cause disease
Rhizobium
Helps to fix nitrogen for plants, creates root nodules
Transient bacteria
The ones we pick up from our environment
Zone of inhabition
Big colony not allowing other bacteria to grow
All purpose media
You can grow anything on this media
TSA and TSB
